The new 1.2-mile paved stretch of trail in the Washington Park Arboretum is still awaiting its grand opening -- now set for April 8.

But pedestrians and cyclists are already testing out the long-planned addition to the park, which has been underway for more than three years (it was part of an arboretum master plan dating back to 2001) and spans the distance between the park’s north and south entrances, at E Madison Street and Foster Island Road.

Forming a 2.5-mile internal loop with Arboretum Drive, the new trail section offers access to 21 new and 30 renovated plant exhibits. Rockeries, wetland drains and ponds along Arboretum Creek have been added to help control the water flow in the new design—a herculean effort, according to Garrett Farrell, a senior capital projects manager of Seattle Parks and Recreation.

“This is one of the biggest moves in the Arboretum since it was created,” he says. In the end, it’s one every visitor will appreciate. “We want to leave it better than we found it.”